DAVIS. — A PQ PLANE FOR THERMODYNAMIC CYCLIC ANALYSIS. 639 



thing is to decrease the amount of air handled, as will often be the 

 case,* _then the best point iu the area is the intersection of the curve 

 V = V with the curve T^ = '1\. Under such circumstances there is a 

 perfectly definite and comparatively low ratio of compression which 

 should not be exceeded. The intersection of the curves V — V and 

 T^ = Tg may bo called for convenience the V 2\ corner, or, less ex- 

 plicitly, 2u V T corner, 

 p 



50 



100 



150 



350 



400 



450 500 



QlnBTU 



200 250 300 



Figure 6. 



Type A. Efficiency. Tlie efficiency of a Brayton cycle is independent of its 

 breadth. 



All four of these families of curves are plotted together for reference 

 on the first working chart, the 7\ and V curves as lines, the E curves 

 in dots, and the W curves in dashes. Of course the result is a compli- 

 cated plane; but it is believed that a study of the figures in the text 

 will make this chart intelligible and that the information of various 

 kinds which it can afford will repay one for this trouble. To avoid un- 

 necessary confusion, the efficiency lines between E =^ .00 and E =i .25 



* Both tlie size of the necessary machinery and the inefficiency of air com- 

 pressors point that way. Highly compressed air is sometimes a more expensive 

 commodity than fuel. 



